Manufacturing method for packaged green tea beverage

Abstract

The first object is to increase the concentration of tea polyphenols in a beverage, prevent clogging, and shorten the extraction time of tea extract. [Solution] A method for producing a packaged green tea beverage containing a tea extract obtained by drip-extracting tea leaves, the method comprising the steps of: using first tea leaves and second tea leaves with different hydraulic conductivity as raw materials, loading the first tea leaves with the greater hydraulic conductivity into a drip extractor, and then loading the second tea leaves with the lesser hydraulic conductivity into the extractor to form a tea leaf layer in the extractor having a configuration in which a second tea leaf layer made of the second tea leaves is stacked on top of a first tea leaf layer made of the first tea leaves, the tea leaf layer having a hydraulic conductivity of 70 to 93 as a whole, an aqueous solvent is supplied to the tea leaf layer from above and the aqueous solvent is withdrawn from below the tea leaf layer to obtain a tea extract, filtering the obtained tea extract to obtain a filtrate, and blending, sterilizing, and filling the filtrate into a container. This is a method for producing a packaged green tea beverage, the method comprising the steps of:

Description

[Technical field]

[0001] The present invention relates to a method for producing a packaged green tea beverage. [Background technology]

[0002] The polyphenols contained in green tea (also known as "tea polyphenols") have been reported to have a variety of physiological functions, including antioxidant effects, anticancer effects, blood sugar lowering effects, blood cholesterol lowering effects, and triglyceride lowering effects. In recent years, there has also been a trend to seek "strong" green tea beverages as a way to vary flavors. From this perspective, in recent years, there has been a demand for packaged green tea beverages with high tea polyphenol concentrations.

[0003] Conventionally, tea extract used in the preparation of packaged green tea beverages has been prepared by introducing tea leaves and heated extraction water into an open extraction tank generally called a kneader, stirring the mixture, and then removing the tea extract. However, the kneader extraction method has limitations in terms of increasing the tea polyphenol concentration. When trying to further increase the tea polyphenol concentration, the kneader extraction method has the problem that the tea leaves are broken down into small pieces by agitation, resulting in an increase in unpleasant flavors and a decrease in transparency. As a means for solving these problems, for example, a method of extracting tea using a drip extractor (also called a "column extractor" or "column type extractor") used for extracting coffee can be considered.

[0004] Patent Document 1, for example, discloses a method for producing a green tea beverage by drip extraction using a drip extractor, in which tea leaves and water or hot water are charged into a column extractor so that the ratio B / A of the tea leaf height A to the liquid level B of the water or hot water is 0.8 to 3.3, and then water or hot water is supplied from the top of the column, and when the tea extract is extracted from the bottom of the column, the ratio C / A of the liquid level C to the tea leaf height A at the time of charging is adjusted to 0.8 to 3.3.

[0005] Patent Document 2 discloses a method for producing tea extract, which comprises the following steps (1) to (3): (1) The process of preparing multiple layers of tea on a tea holding plate mounted in a column-type extractor. (2) A step of supplying extraction water from the lower or upper part of the extractor and contacting the extraction water with the layered tea. (3) Discharge of tea extract

[0006] Patent Document 3 discloses a method for producing tea extract, which includes the following steps. (S A ) A step of feeding tea leaves A into a column extractor; (S B ) supplying extraction water B from the bottom of the extractor; (S C ) supplying extraction water C from the upper part of the extractor; (S D ) A step of supplying extraction water D from the top while extracting tea extract from the bottom of the extractor.

[0007] Patent Document 4 discloses a method for producing tea extract, which comprises loading three or more types of tea ingredients in layers on a tea holding plate attached to a column-type extractor, supplying extraction water into the extractor and discharging the tea extract, in which the wet densities of the three or more types of tea ingredients are compared, and any one of the tea ingredients excluding the tea ingredients having the maximum and minimum wet densities is loaded in the uppermost layer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2006-197920 A [Patent Document 2] JP 2009-82110 A [Patent Document 3] JP 2010-57377 A [Patent Document 4] JP 2011-139655 A Summary of the Invention [Problem to be solved by the invention]

[0009] The drip extraction method has the advantage that it is possible to obtain a tea extract with a higher tea polyphenol concentration than the kneader method, and that the production time can be shortened. On the other hand, in order to increase the tea polyphenol concentration, it is necessary to load a larger amount of tea leaves with a high tea polyphenol extractability, for example, tea leaves with a relatively large surface area, into the vessel. In that case, clogging occurs in the extractor, which lengthens the time required to extract the tea extract, resulting in a problem of reduced productivity. It has also been reported that when drip extraction is used, the tea extract tends to turn red. Therefore, the first object of the present invention is to provide a new method for producing a packaged green tea beverage that can increase the concentration of tea polyphenols in the beverage while preventing clogging and shortening the extraction time for the tea extract.A second object of the present invention is to provide a method for producing a packaged green tea beverage that can also prevent the beverage from turning red. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention proposes the following aspects.

[0011] [1] A first aspect of the present invention is a method for producing a packaged green tea beverage containing a tea extract obtained by drip-extracting tea leaves, comprising: Using first and second tea leaves having different hydraulic conductivity as raw materials, the first tea leaves having a larger hydraulic conductivity are put into a drip extractor, and then the second tea leaves having a smaller hydraulic conductivity are put into the extractor to form a tea leaf layer in the extractor, the tea leaf layer having a configuration in which a first tea leaf layer made of the first tea leaves is layered on a second tea leaf layer made of the second tea leaves, and the tea leaf layer as a whole has a hydraulic conductivity of 70 to 93 as described below; An aqueous solvent is supplied to the tea leaf layer from above, and the aqueous solvent is withdrawn from below the tea leaf layer to obtain a tea extract; The method for producing a bottled green tea beverage is characterized in that the obtained tea extract is filtered to obtain a filtrate, and the filtrate is compounded, sterilized, and packed into containers.

[0012] The hydraulic conductivity of the entire tea leaf layer was measured by placing each of the above tea leaves in a drip extractor (with a pipe diameter of φ4 mm) as described above, and determining that the mass per unit area was 6 g / cm 2 In a test in which a tea leaf layer is formed so that the tea leaves meet the above requirement, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from below the tea leaf layer under its own weight, the hydraulic conductivity k is calculated using the following formula. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml g / cm 2 s) V: Amount of tea extract extracted (mL) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

[0013] [2] A second aspect of the present invention is a method for producing a packaged green tea beverage, characterized in that in the first aspect, the first tea leaves have a hydraulic conductivity of 60 or more and 90 or less, and the second tea leaves have a hydraulic conductivity of 30 or more and less than 60, as described below.

[0014] The hydraulic conductivity of each tea leaf was measured by putting each tea leaf into a drip extractor (with a pipe diameter of φ4mm) and measuring the mass per unit area of ​​6g / cm 2 In a test in which a tea leaf layer is formed so that the tea leaves meet the above requirement, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from below the tea leaf layer under its own weight, the hydraulic conductivity k is calculated using the following formula. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml g / cm 2 s) V: Amount of tea extract extracted (mL) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

[0015] [3] A third aspect of the present invention is a method for producing a packaged green tea beverage according to the first or second aspect, characterized in that the tea extract before filtration has a transmitted light absorbance value (A) of 0.12 to 0.22 at a wavelength of 660 nm.

[0016] [4] A fourth aspect of the present invention is a method for producing a packaged green tea beverage according to any one of the first to third aspects, wherein the green tea beverage after packaging has a tea polyphenol content of 86 to 200 mg / 100 mL%, a transmittance at 500 nm of 65% or less, and a ratio of the transmittance at 580 nm to the transmittance at 780 nm (580 nm / 780 nm) of 0.85 or more. Effect of the Invention

[0017] The method for producing a packaged green tea beverage proposed by the present invention employs drip extraction, which can obtain a tea extract with a higher tea polyphenol concentration than extraction using a kneader, and can shorten the production time.Furthermore, by adding the first tea leaves with a higher hydraulic conductivity into an extractor, and then adding the second tea leaves with a lower hydraulic conductivity, a tea leaf layer is formed in the extractor, in which a second tea leaf layer made of the second tea leaves is layered on top of a first tea leaf layer made of the first tea leaves, and the tea leaf layer as a whole has a hydraulic conductivity of 70 to 93, as described below. This can increase the tea polyphenol concentration in the beverage, and at the same time, prevent clogging and shorten the extraction time of the tea extract. Furthermore, by adjusting the hydraulic conductivity of the first tea leaves and the second tea leaves to be within a predetermined range, it is possible to prevent the tea extract, i.e., the green tea beverage, from turning red, and to produce a packaged green tea beverage that can be evaluated as golden in color. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] An example of an embodiment of the present invention will be described below, however, the present invention is not limited to the embodiment described below.

[0019] <<Production method of the present invention>> A method for producing a packaged green tea beverage according to one embodiment of the present invention (also referred to as the "production method of the present invention") is a method in which tea leaves are drip-extracted to obtain a tea extract (extraction step), extraction residue is removed from the tea extract as necessary (coarse filtration step), the tea extract is centrifuged as necessary (centrifugation step), the tea extract is filtered using a specified filter aid (filtration step), and then a blending step and a sterilization / packaging step are carried out to produce a packaged green tea beverage. However, the manufacturing process is merely an example, and the order of the steps can be changed, and other steps can be inserted between the steps.

[0020] <Raw material tea> The green tea leaves, i.e., raw tea leaves, can be any type of tea as long as they are picked from the tea plant (scientific name: Camellia sinensis), regardless of the variety, place of origin, picking time, picking method, cultivation method, etc. Raw tea leaves (including leaves and stems) can be used as raw tea leaves. Furthermore, raw tea leaves that have been subjected to a process for stopping enzyme activity by steaming or roasting the raw tea leaves can also be used as raw tea leaves. Finished tea obtained by subjecting the above-mentioned raw tea to a currently known finishing process can also be used as raw tea leaves. As the crude tea, any type of tea can be used as the raw material tea leaves, for example, Sencha, Kamairicha, Kabusecha, Gyokuro, Tencha, Matcha, Bancha, Hojicha, Steamed Tamaryokucha, Kamairoise Tamaryokucha, Ureshinocha, Aoyagicha, etc. Two or more types of these crude teas may be combined, or flavorings may be added.

[0021] (First and second tea leaves) In the production method of the present invention, it is preferable to use first and second tea leaves having different hydraulic conductivity, i.e., the first tea leaves having a larger hydraulic conductivity and the second tea leaves having a smaller hydraulic conductivity.

[0022] Here, the hydraulic conductivity of the tea leaves is measured by pouring each type of tea leaves into a drip extractor (with a pipe diameter of φ4 mm) and piling them up, and the mass per unit area is 6 g / cm 2In a test in which a tea leaf layer is formed so that the tea leaves meet the above requirement, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from below the tea leaf layer under its own weight, the hydraulic conductivity k is calculated using the following formula. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml g / cm 2 s) V: Amount of tea extract extracted (mL) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

[0023] The hydraulic conductivity of tea leaves can be adjusted by the amount of tea leaves, the type of tea (first harvest, autumn / winter bancha, etc.), shape (degree of twist), size, degree of roasting (roasted / steamed, rough tea / finished tea, heating temperature during finishing), etc.

[0024] The first tea leaves are preferably tea leaves that are less likely to clog, i.e., tea leaves with a high hydraulic conductivity. Therefore, the hydraulic conductivity of the first tea leaves is preferably 60 or more and 90 or less, more preferably 65 or more, and even more preferably 70 or more. On the other hand, the second tea leaves may be tea leaves that are prone to clogging, i.e., tea leaves with a low hydraulic conductivity. Therefore, it is preferable that the hydraulic conductivity of the second tea leaves is 30 or more and less than 60, and more preferably 35 or more, and even more preferably 40 or more.

[0025] The difference in hydraulic conductivity between the first and second tea leaves is preferably greater than 0, more preferably 5 or more, and even more preferably 10 or more, since it is better for the second tea leaves to be able to easily extract tea polyphenols even if they have a low hydraulic conductivity, whereas if the second tea leaves have a hydraulic conductivity that is too low, the tea extract will become clogged with the second tea leaves and will not be able to be extracted, so the difference is preferably 60 or less, more preferably 50 or less, and even more preferably 40 or less.

[0026] The first tea leaves are required to have a relatively high hydraulic conductivity. From this perspective, the first tea leaves are suitable for roasting, and are therefore suitable to be so-called "hard" tea leaves such as pan-fried tea, roasted tea, and finished tea, for example tea leaves with fully developed buds, tea leaves that have not been rolled much during the crude tea production process, and ripe tea leaves. As for the tea season, among ordinary steamed tea leaves, autumn and winter bancha is preferred. On the other hand, for pan-fried tea, first-grade tea, second-grade tea, third-grade tea, and autumn and winter bancha may be used. From the viewpoint of infusing tea polyphenols sufficiently into the extract, first-grade tea or second-grade tea is more preferred.

[0027] The above-mentioned "Kamairi tea" is tea that has been "roasted" instead of "steamed" in the process of killing the enzymes in the tea leaves. The above-mentioned "Guri tea" is generally not long and thin like Sencha, but is round and round when made into a crude tea. The above-mentioned "roasted tea" is tea that has been heated at high temperatures until it acquires a roasted aroma, and is characterized by having less moisture and being harder than crude tea and general sencha.

[0028] The size of the first tea leaves is preferably such that they can be sieved through a No. 30 sieve and remain on the sieve, and more preferably such that they can be sieved through a No. 20 sieve and remain on the sieve. The tea polyphenol content of the first tea leaves is preferably 5 to 25 g / 100 g, more preferably 8 to 25 g / 100 g, and particularly preferably 10 to 25 g / 100 g. The content of eight types of catechins (epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), gallocatechin gallate (GCg)) is preferably 4 to 20 g / 100 g, more preferably 6 g / 100 g or more or 20 g / 100 g or less, and particularly preferably 8 g / 100 g or more or 20 g / 100 g or less. The ratio of gallate catechins to the eight types of catechins (gallate catechins / 8 types of catechins) is preferably 10 to 80% by mass, more preferably 20% by mass or more or 70% by mass or less, and particularly preferably 30% by mass or more or 60% by mass or less. The content of the amino acid is preferably 0.1 to 5 g / 100 g, more preferably 0.1 to 4.5 g / 100 g, and particularly preferably 0.1 to 4 g / 100 g. The total nitrogen is preferably from 2.0 to 10.0 g / 100 g, more preferably from 3.0 to 8.0 g / 100 g, and particularly preferably from 4.0 to 7.0 g / 100 g.

[0029] On the other hand, the second tea leaves are preferably tea leaves having a relatively low hydraulic conductivity but high tea polyphenol extractability, for example tea leaves having a relatively large surface area. From this viewpoint, the second tea leaves are preferably so-called "soft" tea leaf raw materials such as ordinary steamed tea, deep steamed tea, and extra steamed tea. From the standpoint of softness, for example, "mil buds" that are picked early, or tea leaves that are rolled extensively during the crude tea manufacturing process, such as tea leaves that are rolled strongly during the rolling process, are preferred. From the viewpoint of infusing tea polyphenols sufficiently into the extract, first or second harvest tea is preferable. Furthermore, rough tea is preferred over finished tea.

[0030] The above-mentioned "regular steamed tea" is tea that has been steamed in a process that stops the activity of enzymes in the tea leaves. The leaves are softer than "pan-fried tea" and tend to absorb water and spread easily. The above-mentioned "deep steamed tea" and "extremely steamed tea" are teas that have been steamed for a long time during the process of making rough tea, which stops the action of enzymes in the tea leaves. Since the "normally steamed" shape is destroyed, the rough tea has a smaller shape than "pan-fried tea" or "normally steamed tea".

[0031] As described above, the second tea leaves are preferably fine tea leaves because they have a relatively large surface area. From this viewpoint, it is preferable to sieve the second tea leaves through a No. 4 sieve and remove the tea leaves on the sieve, and it is particularly preferable to sieve the second tea leaves through a No. 8 sieve and remove the tea leaves on the sieve. The second tea leaves are preferably so-called "fine" tea leaf raw materials such as ground tea, powdered tea, etc.

[0032] The tea polyphenol content of the second tea leaves is preferably from 10 to 30 g / 100 g, more preferably from 12 to 30 g / 100 g, and particularly preferably from 15 to 30 g / 100 g. The content of eight types of catechins (epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), and gallocatechin gallate (GCg)) is preferably 8 to 24 g / 100 g, more preferably 10 g / 100 g or more or 24 g / 100 g or less, and particularly preferably 12 g / 100 g or more or 24 g / 100 g or less. The ratio of gallate catechins to the eight types of catechins (gallate catechins / 8 types of catechins) is preferably 20 to 90% by mass, more preferably 30% by mass or more or 80% by mass or less, and particularly preferably 40% by mass or more or 70% by mass or less. The amino acid content is preferably 0.1 to 6 g / 100 g, more preferably 0.4 g / 100 g or more or 5 g / 100 g or less, and particularly preferably 0.8 g / 100 g or more or 4 g / 100 g or less. The total nitrogen is preferably from 1.0 to 9.0 g / 100 g, more preferably from 1.5 to 7.5 g / 100 g, and particularly preferably from 2.0 to 6.0 g / 100 g.

[0033] As described above, in terms of size, it is preferable that the first tea leaves are relatively large and the second tea leaves are relatively small. From this viewpoint, it is preferable that the first tea leaves are tea leaves that have sufficiently grown, for example, tea leaves with a hardening degree of 50 to 70, or tea leaves that have not been rolled much in the crude tea manufacturing process, for example, tamaryokucha. On the other hand, the second tea leaves include tea leaves that have been rolled a lot during the crude tea manufacturing process, such as tea leaves that have been rolled with strong pressure during the rolling process, so-called "fine" tea leaves such as crushed tea and powdered tea, for example, soft tea leaves that are picked early, for example, tea leaves with a hardening degree of 30 to 50.

[0034] The hydraulic conductivity of the first and second tea leaves can also be adjusted by sieving. For example, by removing tea leaves that fall under a sieve of No. 30 or No. 20, i.e., by removing fine tea leaves, the hydraulic conductivity of the first and second tea leaves can be increased. On the other hand, by removing tea leaves that fall over a sieve of No. 4 or No. 8, i.e., by removing large tea leaves, the hydraulic conductivity of the first and second tea leaves can be decreased. In the present invention, since it is desirable to adjust the hydraulic conductivity of the first tea leaves to be higher than that of the second tea leaves, when adjusting the size of the first tea leaves by sieving, it is preferable to remove tea leaves that pass through a No. 30 sieve, and it is more preferable to remove tea leaves that pass through a No. 20 sieve. On the other hand, since it is desirable to extract tea polyphenols from the second tea leaves more efficiently than from the first tea leaves, when adjusting the size of the second tea leaves by sieving, it is preferable to remove tea leaves that pass through a No. 4 sieve, and it is more preferable to remove tea leaves that pass through a No. 8 sieve.

[0035] The bulk density of the first tea leaves is 0.5 g / cm3 so that the tea leaves are less likely to be compacted and are easier to extract from the extractor. 3 It is preferable that the density is 0.4 g / cm or less. 3 The following is 0.33g / cm 3 On the other hand, in terms of increasing the extractability of tea polyphenols, it is more preferable that the concentration is 0.2 g / cm or less. 3 More preferably, it is 0.21 g / cm or more. 3 Above all, 0.22g / cm 3 More preferably, it is equal to or greater than this. On the other hand, the bulk density of the second tea leaves is 0.22 g / cm3, which increases the surface area of ​​the tea leaves and enhances the extractability of tea polyphenols. 3 More preferably, it is 0.24 g / cm or more. 3Above all, 0.26g / cm 3 On the other hand, from the viewpoint of preventing compaction in the second tea leaf layer, it is more preferable that the density is 1.0 g / cm or more. 3 It is preferable that the density is 0.6 g / cm or less. 3 More preferably, it is 0.5 g / cm or less. 3 It is particularly preferred that:

[0036] <Extraction process> In the method of the present invention, a drip extractor is used, and first tea leaves having a larger hydraulic conductivity are introduced and piled up in the extractor, and then second tea leaves having a smaller hydraulic conductivity are introduced and piled up in the extractor to form a tea leaf layer in the extractor having a structure in which a first tea leaf layer made of the first tea leaves is layered on a second tea leaf layer made of the second tea leaves, and an aqueous solvent is supplied to the tea leaf layer from above and the aqueous solvent is withdrawn from below the tea leaf layer to obtain a tea extract. In this case, it is preferable to form the tea leaf layer so that the hydraulic conductivity of the entire tea leaf layer is within a predetermined range.

[0037] One method to obtain tea extract with a high concentration of tea polyphenols is to put a large amount of tea leaves into the extractor. However, depending on the type of tea leaves, there is a concern that increasing the amount of tea leaves put in may cause clogging and increase the extraction time. In particular, if a large amount of so-called "soft" tea leaves such as normal steamed or deep steamed raw materials are put in, clogging is likely to occur. Therefore, first tea leaves with a higher hydraulic conductivity are placed into the extractor, and then second tea leaves with a lower hydraulic conductivity are placed into the extractor to form a tea leaf layer in which a first tea leaf layer made of the first tea leaves is layered on top of a second tea leaf layer made of the second tea leaves, and the tea leaf layer as a whole has a hydraulic conductivity within a predetermined range, for example 70 to 93.By then extracting, it is possible to produce a tea extract with a high concentration of tea polyphenols without clogging and in a shorter extraction time, i.e., extraction time.

[0038] (extractor) In the production method of the present invention, it is preferable to carry out drip extraction using a drip extractor. Drip extraction not only allows tea-derived ingredients to be extracted with a smaller amount of hot water than kneader extraction, but also allows more tea leaves to be extracted at once, shortening the production time and allowing more tea-derived ingredients to be extracted. This makes it suitable for industrial production of tea beverages with high tea polyphenol concentrations. In addition, since green tea beverages tend to oxidize over the longer production time and change color from gold to red, the use of the drip method has the advantage of shortening the extraction time and making it easier to obtain a green tea beverage that is rich in tea polyphenols and has a transparent golden color. However, the above-mentioned problems of the present invention cannot be solved by merely adopting drip extraction.

[0039] The drip extractor may be any device that includes a supply means for supplying extraction water from above an extractor consisting of a closed extraction column, an extraction means for extracting tea extract from below the extractor, and a tea leaf holding plate for holding tea leaves inside. The means for supplying the extraction water to the tea leaf layer in the extractor may be any means that supplies the extraction water from above the tea leaf layer via a shower nozzle or the like, but is not limited to a shower nozzle. The means for extracting the tea extract may be any means that discharges the tea extract from the extraction pipe via a valve. The tea extract may be extracted by its own weight, or may be extracted using the power of a pump or the like. The tea holding plate for holding tea is not particularly limited as long as it can separate tea leaves from tea extract. For example, a wire mesh is preferred, and flat, conical, pyramidal, or other shapes can be used. In addition, the mesh size of the wire mesh is preferably 20 to 150 mesh from the viewpoint of substantially separating the prepared tea from the tea extract, and more preferably 40 mesh or more or 120 mesh or less, and even more preferably 60 mesh or more or 100 mesh or less.

[0040] (Formation of tea leaf layer) First tea leaves having a larger hydraulic conductivity are put into the extractor, and the first tea leaves are piled up to form a first tea leaf layer, and then second tea leaves having a smaller hydraulic conductivity are put into the extractor, and the second tea leaves are piled up on the first tea leaf layer to form a second tea leaf layer, thereby forming a tea leaf layer in the extractor.

[0041] It is preferable to pile the first tea leaves and level the top surface of the tea leaves to a uniform height, and then to add the second tea leaves, pile them up, and level the top surface of the tea leaves to a uniform height. In this case, the means for leveling the top surface of the tea may be a stirring means having a horizontal bar or horizontal blades attached to a vertical bar, but is not limited to this means.

[0042] From the viewpoint of sufficient extraction of tea polyphenols, the amount of the first tea leaves and the second tea leaves added is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 50 parts by mass or more, per 100 parts by mass of the first tea leaves added. On the other hand, from the viewpoints of quality and production efficiency, in order to shorten the extraction time, the amount of the second tea leaves added is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and even more preferably 100 parts by mass or less, per 100 parts by mass of the first tea leaves added.

[0043] From the same viewpoint, the height of the second tea leaf layer in the extractor is preferably 10 or more relative to the height of the first tea leaf layer of 100, more preferably 20 or more, and even more preferably 30 or more. On the other hand, the height of the second tea leaf layer is preferably 200 or less relative to the height of the first tea leaf layer of 100, more preferably 150 or less, and even more preferably 100 or less.

[0044] The permeability coefficient of the tea leaf layer formed by stacking the second tea leaf layer on the first tea leaf layer, i.e., the permeability coefficient of the entire tea leaf layer, is preferably 70 or more in order to shorten the extraction time from the standpoints of quality and production efficiency, and is more preferably 75 or more, and even more preferably 80 or more. On the other hand, from the viewpoint of increasing the tea polyphenol concentration, it is preferably 93 or less, more preferably 90 or less, and even more preferably 88 or less. The permeability coefficient of the tea leaf layer can be adjusted by changing the permeability coefficient and amount of each of the first tea leaf layer and the second tea leaf layer.

[0045] The hydraulic conductivity of the entire tea leaf layer was measured by placing each of the above tea leaves in a drip extractor (with a pipe diameter of φ4 mm) as described above, and measuring the mass per unit area to be 6 g / cm 2 In a test in which a tea leaf layer is formed so that the tea leaves meet the above requirement, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from below the tea leaf layer under its own weight, the hydraulic conductivity k is calculated using the following formula. The drip extractor used in the above test may be different from the extractor used in the actual extraction. Similar results can be obtained if the extractor has a specified diameter (diameter of the drawing pipe: φ4mm). In this case, if the first and second tea leaves used in the actual extraction are put into the extractor in the same ratio as in the actual extraction, the measured hydraulic conductivity of the entire tea leaf layer will be approximately the same as the hydraulic conductivity of the tea leaf layer formed in the actual extraction, even if the drip extractor used in the above test is a different size from the extractor used in the actual extraction.

[0046] k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml g / cm 2 s) V: Amount of tea extract extracted (mL) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

[0047] In order to form a tea leaf layer such that the hydraulic conductivity of the entire tea leaf layer falls within the above range, the hydraulic conductivity of the first tea leaves and the second tea leaves, the amounts of the first tea leaves and the second tea leaves added, etc. may be adjusted, but the present invention is not limited to these means.

[0048] (Aqueous Solvent) Examples of the water-soluble solvent used for extraction include pure water (including hard water, soft water, and ion-exchanged water), as well as an aqueous solution containing ascorbic acid and pH-adjusted water. The extraction temperature, i.e., the temperature of the water-soluble solvent used for extraction, is preferably adjusted appropriately between 0 and 100° C. From the viewpoint of increasing the concentration of tea polyphenols, a temperature of 70 to 100° C. is preferable, and more preferably, extraction is performed at a temperature of 72° C. or higher or 99° C. or lower, more preferably, 75° C. or higher or 98° C. or lower, and even more preferably, 78° C. or higher or 97° C. or lower.

[0049] (Tea extract extraction speed) The extraction speed of the tea extract is controlled by, for example, placing a tea leaf separation mesh (with an area of ​​50 cm) at the bottom. 2 When a drip-type cylindrical extractor (φ98 mm) equipped with a mesh size of 1.5 mm, 80 mesh, is used and the tea extract is extracted from an extraction pipe with a diameter of φ4 mm, from the viewpoint of production efficiency (extraction time), the extraction speed is preferably 550 mL / min or more, more preferably 600 mL / min or more, and even more preferably 700 mL / min or more. The faster the tea extract extraction speed, the better, but it is thought to be difficult to achieve an extraction speed of 5000 mL / min or more. The extraction rate of the tea extract can be adjusted by adjusting the type and amount of tea leaves, the diameter of the outlet pipe, i.e. the diameter of the extraction pipe, suction by a pump or the like, the opening of the valve in the outlet pipe, the retention time between the first and second showers, etc.

[0050] <Rough filtration process> The tea extract obtained in the extraction step is preferably subjected to coarse filtration, if necessary, to remove extraction residues such as tea leaves and large fine powder. For example, a stainless steel filter, a flannel cloth, a strainer, or any other filtering method currently used to remove extraction residues can be used.

[0051] The tea extract after the crude filtration step may be cooled to about 5 to 40°C as necessary, and at the same time, or before or after, ascorbic acid, sodium ascorbate, or the like may be added to the tea extract to make it acidic (pH 4 to 5). Cooling the tea extract or adjusting the acidity can prevent oxidation of the extracted components, and can also precipitate components that cause primary sediment, thereby increasing the efficiency of the subsequent centrifugation step.

[0052] <Centrifugation process> The tea extract that has been subjected to the coarse filtration step is preferably subjected to centrifugation, if necessary. Centrifugation may be carried out under conditions of, for example, a flow rate of 200 to 500 L / h and a rotation speed of 5,000 to 20,000 rpm. In this case, the clarity (T%) of the final packaged green tea beverage can be adjusted by changing the flow rate, rotation speed, centrifugal sedimentation area (Σ), etc. As described above, it is preferable to cool the tea extract to about 5 to 40° C. before centrifuging, but cooling is not essential.

[0053] Fine powder can be removed by centrifugation, but centrifugation is not always necessary if there is another process capable of removing fine powder. By carrying out centrifugation before the filtration step, the burden on the filtration step can be reduced. For example, the filtration time can be shortened by increasing the permeation flow rate and decreasing the permeation pressure. However, since fine powder can also be removed in the filtration step, it is possible to omit centrifugation when carrying out the filtration step, although the burden will be somewhat greater.

[0054] In place of centrifugation, filtration using flannel cloth (Flannel filtration), filtration with a 80 to 200 mesh stainless steel filter, filtration with a back filter with 1 to 100 μm openings, or treatment to reduce the catechin content with PVPP may be performed.

[0055] <Filtration process> In the filtration step, the tea extract is filtered using a specific filter aid. In this case, it is preferable to use a filter aid derived from a mineral from the viewpoint of its effect on the flavor of the green tea beverage. Examples of mineral-derived filter aids include diatomaceous earth derived from fossil minerals, perlite derived from volcanic rocks, etc. Among these, diatomaceous earth is preferred in terms of liquid permeability.

[0056] Diatomaceous earth is a type of soil that is made up of minute diatom shells that have accumulated over many years as phytoplankton called diatoms accumulate on the bottom of oceans and lakes and fossilize.The diameters of the diatom shells are several to several tens of μm, and there are countless minute holes of 0.1 to 1.0 μm on the surface, so a dense cake layer of filter aid is formed on wire mesh or filter cloth, which allows clear liquid to be obtained during filtration. The main component of diatomaceous earth is silica (SiO2), specifically amorphous silica, and for use as a filter aid it is generally purified by calcination.

[0057] Diatomaceous earth filtration is a cake filtration that uses diatomaceous earth as a filter aid. The diatomaceous earth filtration method involves forming an auxiliary layer (precoat) made of diatomaceous earth on the surface of the filter carrier, and, if necessary, injecting (body feeding) the diatomaceous earth filtering agent into the raw liquid (tea extract as unfiltered liquid), while feeding the raw liquid (tea extract as unfiltered liquid) to the auxiliary layer. Here, "precoating" refers to dispersing an auxiliary agent in a clear liquid prior to the filtration operation, circulating this, and forming a layer of the auxiliary agent several mm thick on the surface of the filtration carrier (e.g., a metal leaf, thick filter pad, laminated metal candle, ceramic candle, etc.), which prevents suspended solids from directly adhering to the filter material and causing contamination, and also improves the clarity of the filtrate. As for the filtration method, it is possible to adopt membrane filtration such as ultrafiltration, microfiltration, precision filtration, reverse osmosis membrane filtration, electrodialysis, and biological functional membrane filtration, or a combination of two or more of these. However, because tea beverages are susceptible to oxygen deterioration, in terms of flavor balance, it is more suitable to adopt clarifying filtration such as cake filtration using a filter aid than the cross-flow method generally used in membrane filtration and ultrafiltration.

[0058] In addition, diatomaceous earth may be mixed with other filter aids such as silica gel, perlite, cellulose, etc.

[0059] In the filtration step, it is preferable to use a filter aid having a median diameter (D50) in the cumulative particle diameter distribution (volume basis) after swelling of 5 to 30 μm. It is preferable to use a filter aid with a D50 of 5 μm or more after swelling because it allows the drinker to feel a rich aftertaste due to the aroma, whereas it is preferable to use a filter aid with a D50 of 30 μm or less because it allows the drinker to drink without feeling rough on the tongue. From this viewpoint, the filter aid used has a median diameter (D50) in the cumulative distribution (volume basis) of particle diameter after swelling of 5 μm or more, more preferably 7 μm or more, more preferably 10 μm or more, and more preferably 30 μm or less, more preferably 25 μm or less, more preferably 20 μm or less. The swelling conditions for measuring the cumulative particle size distribution (volume basis) of the swollen filter aid are as follows: 10 g of each filter aid is dispersed in 50 times its amount of pure water and immersed for 15 minutes to allow it to swell.

[0060] The filter aid used preferably has a Darcy of 0.03 to 0.25. If the darcy of the filter aid is 0.03 or more, the overall richness of the tea components can be felt even after aging, which is preferable, whereas if it is 0.25 or less, the generation of sediment over time can be suppressed, which is preferable. From this viewpoint, the filter aid used preferably has a Darcy of 0.03 or more, more preferably 0.05 or more, and even more preferably 0.25 or less, more preferably 0.23 or less, and even more preferably 0.20 or less. In addition, "filter aid with Darcy of 0.03 to 0.25" means a filter aid with Darcy permeability K in the range of 0.03 to 0.25. "Darcy permeability K" is one of the indicators of the permeability of a filter aid, and can be obtained by the water permeability method or the air permeability method. Currently, "Darcy" is so commonly used that filter aids can be purchased by specifying this value.

[0061] <Mixing process> In the preparation step, water (hard water, soft water, ion-exchanged water, natural water, etc.) is added to dilute the tea extract so that the concentration of the tea leaves is 8 g / L to 16 g / L, and ascorbic acid, sodium ascorbate, sodium bicarbonate, sugars, dextrin, flavorings, emulsifiers, stabilizers, or other flavoring materials, or a combination of two or more of these, are added as necessary to mainly adjust the pH, concentration, and taste. For example, the pH can be adjusted to about 6 and the Brix can be adjusted to about 0.3. One of the features of the production method of the present invention is that it can increase the tea polyphenol concentration in a beverage without adding a tea polyphenol composition such as a catechin preparation.

[0062] <Sterilization / container filling process> Heat sterilization may be carried out by reheating (hot packing) canned beverages as necessary, filling them, and then retort sterilization (for example, heat sterilization at 121°C for 7 minutes under appropriate pressure (e.g., 1.2 mmHg)). In the case of plastic bottled beverages, UHT sterilization (holding the prepared liquid at 120 to 150°C for 1 to several tens of seconds) may be carried out.

[0063] The above-mentioned manufacturing steps, i.e., the manufacturing process for manufacturing a green tea beverage through the extraction step, the coarse filtration step, the centrifugation step, the filtration step, the blending step, the sterilization step and the container filling step, are merely examples of the present invention and are not limited thereto. For example, the order of the steps may be changed or other steps may be added.

[0064] <Beverage (tea extract)> (Tea polyphenol concentration) The green tea beverage after being filled into a container preferably contains tea polyphenols at 86 mg / 100 mL% or more, more preferably 90 mg / 100 mL% or more, even more preferably 100 mg / 100 mL% or more, and even more preferably 130 mg / 100 mL% or more. On the other hand, from the viewpoint of ease of consumption as a beverage, it is preferable for the tea to contain tea polyphenols at a ratio of 200 mg / 100 mL% or less, more preferably 160 mg / 100 mL% or less, even more preferably 155 mg / 100 mL% or less, and even more preferably 150 mg / 100 mL% or less. In this case, tea polyphenols is a general term for plant components that have multiple phenolic hydroxyl groups in their molecules, mainly consisting of eight types of catechins (epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), gallocatechin gallate (GCg)), which are commonly known as tannins, and the amount of tea polyphenols is the total amount of tannin-like substances including these eight types of catechins.

[0065] (Transmitted light absorbance value (A)) The tea extract before the filtration step obtained as described above has a transmitted light absorbance value (A) of preferably 0.12 or more at a wavelength of 660 nm, more preferably 0.13 or more, and even more preferably 0.15 or more, from the viewpoint of indicating that a tea extract with a high tea polyphenol content has been obtained, while the absorbance value (A) is preferably 0.22 or less, more preferably 0.21 or less, and even more preferably 0.19 or less, from the viewpoint of reducing the load in the filtration step after extraction.

[0066] (Light transmittance) From the viewpoint that the green tea beverage after being filled into a container preferably has a high tea polyphenol content and is golden and transparent, it is preferable that the tea polyphenol content is 86 to 200 mg / 100 mL%, the transmittance at 500 nm is 65% or less, and the ratio of the transmittance at 580 nm to the transmittance at 780 nm (580 nm / 780 nm) is 0.85 or more.

[0067] The tea polyphenol content is the same as above.

[0068] If the transmittance at 500 nm, which is a blue wavelength, is 65% or less, the liquid color appears dark. Therefore, the transmittance at 500 nm is preferably 65% ​​or less, more preferably 62% or less, and even more preferably 60% or less. However, if the transmittance is too low, it becomes difficult to see the liquid as transparent, so it is preferably 45% or more, more preferably 51% or more, and even more preferably 56% or more.

[0069] It is preferable that the ratio of the transmittance of the yellow wavelength of 580 nm to the transmittance of the red wavelength of 780 nm (580 nm / 780 nm) is 0.85 or more, since this provides a good balance between yellow and red, suppresses the red color, and makes the color closer to gold. From this viewpoint, the ratio (580 nm / 780 nm) is preferably 0.85 or more, more preferably 0.87 or more, and even more preferably 0.90 or more. However, if it is too high, the liquid color becomes light, so it is preferably 0.98 or less, more preferably 0.97 or less, and even more preferably 0.95 or less.

[0070] The thus obtained beverage (tea extract) preferably has a soluble solids content (Brix) of 0.3 or more, more preferably 0.5 or more, and more preferably 2.0 or less, more preferably 1.5 or less.

[0071] The green tea beverage after being filled into a container preferably has a T% (660 nm) of 90.0% or more. If the T% (660 nm) is 90.0% or more, the beverage has high clarity and a refreshing taste. From this viewpoint, it is more preferable that the T% (660 nm) of the green tea beverage after being filled into a container is 93.0% or more. On the other hand, the upper limit can be assumed to be 99.0% or less, and in particular 98.0% or less.

[0072] <<Explanation of terms>> In this specification, when expressed as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, it includes the meaning of "X or more and Y or less", as well as "preferably larger than X" or "preferably smaller than Y". In addition, when it is expressed as "X or more" (X is any number) or "Y or less" (Y is any number), it also includes the intention that "greater than X is preferable" or "less than Y is preferable." EXAMPLES

[0073] The present invention will now be described in further detail with reference to the following examples and comparative examples.

[0074] <Permeability coefficient of tea leaves in the vertical direction> The vertical hydraulic conductivity k of each tea leaf and the entire tea leaf layer was calculated from the amount of tea extract withdrawn per unit area and unit time obtained in the following test and the amount of tea leaves used, using JIS A 1218 (soil hydraulic conductivity test) as a reference, using the following formula: k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml g / cm 2 s) V: Amount of tea extract extracted (ml) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

[0075] <Preliminary test: Test to obtain the vertical hydraulic conductivity of each tea leaf> The hydraulic conductivity of each tea leaf was calculated from the above formula based on the values ​​obtained in the following tests. Tea leaf separation mesh at the bottom (area 50cm 2 A drip-type cylindrical extractor (φ98 mm) equipped with a filter (80 mesh) and a valved outlet pipe (withdrawal pipe diameter of φ4 mm) was used, and a mass per unit area of ​​6 g / cm was placed in the extractor. 2 300 g of each type of tea leaves was added and piled up to form a tea leaf layer in the extractor, and the upper surface of the tea leaf layer was made flat. After supplying hot water from above the tea leaf layer in an amount 20 times the amount of tea leaves, the supply of hot water was stopped and this state was maintained for 5 minutes, after which the valve of the outlet pipe (φ4 mm) was opened and the tea extract was extracted from the extractor under its own weight, and the tea extract was collected until the extraction flow rate reached 0 mL / s. The time from the start to the end of extraction (extraction time) was measured.

[0076] <Preliminary test: Test to obtain the vertical hydraulic conductivity of the entire tea leaf layer> The hydraulic conductivity of the entire tea leaf layer was calculated from the above formula based on the values ​​obtained in the following test. Tea leaf separation mesh at the bottom (area 50cm 2 A drip-type cylindrical extractor (φ98 mm) equipped with a mesh size of 1.8 mm, 80 mesh, and a valved outlet pipe (diameter of the withdrawal pipe) was used. Each tea leaf was placed into the extractor and piled up in the same manner as in the test described below, forming a tea leaf layer in the extractor consisting of a second tea leaf layer stacked on top of a first tea leaf layer, and the upper surface of the tea leaf layer was flattened. After supplying hot water from above the tea leaf layer in an amount 20 times the amount of tea leaves, the supply of hot water was stopped and this state was maintained for 5 minutes, after which the valve of the outlet pipe (φ4 mm) was opened and the tea extract was extracted from the extractor under its own weight, and the tea extract was collected until the extraction flow rate reached 0 mL / s. The time from the start to the end of extraction (extraction time) was measured.

[0077] <Method of measuring tea polyphenol concentration> The tea polyphenol concentration (mg / 100 mL%, shown as "mg%" in the table) of the diluted tea extract or packaged green tea beverage obtained in the Examples and Comparative Examples was measured by the ferric tartrate method. The amount of tea polyphenols is the amount of tannin-like substances including epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC), epigallocatechin gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), and gallocatechin gallate (GCg).

[0078] <Method for measuring absorbance of transmitted light at a wavelength of 660 nm> The diluted tea extract obtained in the Examples and Comparative Examples was shaken well, and 4.0 mL was sampled in a standard plastic cell. The absorbance (Abs) (660 nm) was measured using a Shimadzu UV-1800 ultraviolet-visible spectrophotometer, and the value was expressed as the transmitted light absorbance value (A).

[0079] <Method of measuring light transmittance> The packaged green tea beverages obtained in the Examples and Comparative Examples were shaken well, 4.0 mL of each was sampled in a standard plastic cell, and the transmittance (T%) at 500 nm, 580 nm, or 780 nm was measured using a measuring device: Shimadzu UV-1800 ultraviolet-visible spectrophotometer.

[0080] <Test 1> The following tea leaves were used as the first tea leaves and the second tea leaves.

[0081] Pan-roasted tea leaves: Kagoshima Prefecture, Yabukita variety, first-fed tea, roasting time 2 minutes, bulk density 0.3g / cm 3 , 6g / cm 2 Rough tea with a hydraulic conductivity of 71 (tea polyphenol content: 17.0g / 100g, 8 types of catechin content: 14.0g / 100g, amino acid content: 2.5g / 100g, total nitrogen: 4.5g / 100g) Autumn and winter bancha tea: produced in Shizuoka prefecture, Yabukita variety, regular steamed tea, steaming time 40 seconds, bulk density 0.25g / cm 3 , 6g / cm 2 Rough tea with a hydraulic conductivity of 84 (tea polyphenol content: 15.0g / 100g, 8 types of catechin content: 12.0g / 100g, amino acid content: 0.6g / 100g, total nitrogen: 3.4g / 100g) Regularly steamed tea leaves: Kagoshima Prefecture, Yabukita variety, second batch, steaming time 30 seconds, bulk density 0.33g / cm 3 , 6g / cm 2 Rough tea with a hydraulic conductivity of 48 (tea polyphenol content: 21.0g / 100g, 8 types of catechin content: 17.0g / 100g, amino acid content: 0.8g / 100g, total nitrogen: 3.6g / 100g)

[0082] (control) As a control, the following tea leaves were used as typical tea leaves used in the production of green tea beverages. Regularly steamed tea leaves, Kagoshima Prefecture, Yabukita variety, second batch, steaming time 30 seconds, bulk density 0.3g / cm 3 , 6g / cm 2 The crude tea used had a hydraulic conductivity of 48 (tea polyphenol content: 13.0 g / 100 g, catechin content: 11.0 g / 100 g, amino acid content: 1.9 g / 100 g, total nitrogen content: 4.1 g / 100 g).

[0083] (extractor) As a drip-type extractor, a tea leaf separation wire mesh (80 mesh, area 50 cm) is installed at the bottom. 2 The extractor used was a cylindrical closed extraction column (inner diameter 98 mm) 510 mm above the mesh, equipped with a nozzle and a valved outlet pipe (withdrawal pipe diameter φ4 mm). Extraction water was supplied from above the tea leaf layer via a shower nozzle, and the tea extract was extracted from the bottom of the extractor via a valve through the withdrawal pipe.

[0084] (Formation of tea leaf layer) First tea leaves whose vertical hydraulic conductivity in the total amount of tea leaves is the value shown in the table were added to the extractor, and the first tea leaves were piled up to flatten the upper surface of the first tea leaf layer. Then, second tea leaves whose vertical hydraulic conductivity in the total amount of tea leaves is the value shown in the table were added, and the second tea leaves were piled up to flatten the upper surface of the second tea leaf layer, so that the second tea leaf layer was stacked on top of the first tea leaf layer to form a tea leaf layer whose hydraulic conductivity is the value shown in the table.

[0085] (extraction) Hot water (95°C, ion-exchanged water) was supplied from above to the tea leaf layer through a shower nozzle, and when 20 times the total amount of hot water had been supplied, the supply was stopped and this state was maintained for 5 minutes, after which the valve of the outlet pipe (φ4mm) was opened and the tea extract was extracted from the extraction port under its own weight, and the tea extract was collected until the extraction flow rate reached 0mL / s. The time from the start to the end of extraction (extraction time) was measured and productivity was evaluated.

[0086] (Productivity Evaluation) 4: Compared to the control, the time required for withdrawal was reduced by more than 45%. 3: The withdrawal time was reduced by 35% or more but less than 45% compared to the control. 2: The reduction in withdrawal time was greater than 10% but less than 35% compared to the control. 1: Compared to the control, the reduction in withdrawal time was less than 10% (same as the control).

[0087] <Test 2> As in Test 1, the tea leaves were added, a tea leaf layer was formed, hot water was fed, the tea was retained, and the tea was extracted. The extraction time was kept constant, and the tea extract was collected and the amount of tea extract collected was measured. Thereafter, as in the case of a normal bottled green tea beverage, the tea extract was diluted with ion-exchanged water so that the amount of tea leaves used was 10 g / L, to give a diluted tea extract, which was then subjected to measurement of the tea polyphenol concentration (mg%) and sensory evaluation. The average withdrawal time (485 seconds) obtained from the results of Test 1 was set as the fixed time.

[0088] As a control for the measurement of tea polyphenol concentration (mg%) and the sensory evaluation, a diluted tea extract obtained by diluting the control tea extract obtained in Test 1 in the same manner as above was used.

[0089] (Sensory evaluation) For the diluted tea extracts obtained in the Examples and Comparative Examples, 10 panelists engaged in the production of tea beverages were selected and inspected based on the evaluation content of each item. After consensus was reached, the evaluation with the most votes was adopted.

[0090] 3: Compared to the control, the astringency is stronger. 2: Slightly more astringent than the control. 1: Compared to the control, the astringency is perceived to be the same or weaker.

[0091] (Overall evaluation: Productivity and flavor) ◎: The total score is 7 or more points, and there are no points of 1. ○: The total score is between 5 and 6 points, and there is no score of 1. △: The total score is 4 points or less, and there is no score of 1 point. ×: The total score is 3 points or less, or there is a score of 1 point.

[0092] [Table 1]

[0093] (Consideration) From the results of the above Examples and Comparative Examples, as well as the results of tests conducted by the inventor thus far, it has been found that by adjusting the type and tea season of green tea leaves, etc., to form a tea leaf layer consisting of first tea leaves and second tea leaves taking into consideration the hydraulic conductivity, and in which the hydraulic conductivity of the entire tea leaf layer is adjusted to fall within a predetermined range, it is possible to shorten the extraction time from the extractor and to obtain a tea extract with a high concentration of tea polyphenols. Regarding the amount of tea polyphenols in the tea extract, if the hydraulic conductivity of the tea leaf layer consisting of the first and second tea leaves is too low, the extraction is not completed within the average extraction time, and a sufficient amount of tea polyphenols is not obtained, resulting in a quality that is perceived as "strong." On the other hand, if the hydraulic conductivity of the tea leaf layer consisting of the first and second tea leaves is too high, the amount of tea polyphenols contained in the first and second tea leaves is low, or the extraction time in the extractor is not sufficient, resulting in a sufficient amount of tea polyphenols not being obtained, resulting in a quality that is perceived as "strong."

[0094] <Test 3> The "roasted tea leaves" and "normally steamed tea leaves" used in Example 2 were sieved using sieves No. 8, No. 12, No. 20, or No. 30 to produce tea leaves with different shapes, as shown in Table 2, and tests were conducted using these tea leaves. In Example 13, the "roasted tea leaves" and "normally steamed tea leaves" were further roasted over high heat at 175°C for 7.5 minutes using a roasting machine.

[0095] As in Test 2, tea leaves were added, a tea leaf layer was formed, hot water was supplied, the water was retained, and the tea extract was withdrawn, and the tea extract was collected until the withdrawal flow rate reached 0 mL / s. The recovered tea extract was cooled to 30°C, and the volume of the tea extract and the absorbance value (A) of transmitted light at a wavelength of 660 nm were measured. The color of the water was also evaluated, and then the extract was filtered through a flannel cloth with a mesh size of 50 μm. Next, the filtrate after the flannel filtration was filtered with diatomaceous earth to obtain a diatomaceous earth filtration treatment liquid. In this case, the diatomaceous earth filtration was performed by forming an auxiliary layer (precoat) made of diatomaceous earth on the surface of the filter carrier, and sending the tea extract to the auxiliary layer. In this case, diatomaceous earth with Darcy of 0.16, D50 of 15.0 μm, D90 of 40.0 μm, and D90 / D50 of 2.7 was used. Next, 450 ppm of ascorbic acid was added to the diatomaceous earth filtrate, and the pH was adjusted to 6 with sodium bicarbonate, followed by dilution with ion-exchanged water so that the concentration for the amount of tea leaves used was 14 g / L, followed by UHT sterilization (135°C, 30 seconds), cooling in a plate, and filling into a transparent plastic container (PET bottle) at 85°C to obtain a bottled green tea beverage. The cap was then sterilized by inverting for 30 seconds, and immediately cooled.

[0096] For Examples 14 and 15, in order to evaluate the astringency as a packaged green tea beverage, extraction, diatomaceous earth filtration, addition of ascorbic acid, and pH adjustment were performed in the same manner as in Example 3, and the beverages were diluted with ion-exchanged water to a tea leaf usage concentration of 8 g / L for Example 14 and 16 g / L for Example 15, and then subjected to UHT sterilization (135° C., 30 seconds), cooled in a plate, and filled into a transparent plastic container (PET bottle) at 85° C. to obtain a packaged green tea beverage. The cap was then sterilized by inversion for 30 seconds, and immediately cooled.

[0097] (Evaluation of tea extract) For the diluted tea extracts obtained in the Examples and Comparative Examples, 10 panelists engaged in the production of tea beverages were selected and inspected based on the evaluation content of each item. After consensus was reached, the evaluation with the most votes was adopted.

[0098] ◎: The light blue color is clear (less burden on subsequent filtration) and has a strong appearance (strong tea). ○: The light blue appears clear but lacks a sense of density, or the light blue appears dense but lacks clarity. △: The light blue color is not clear or lacks concentration.

[0099] (Sensory evaluation of packaged green tea beverages) For the packaged green tea beverages obtained in the Examples and Comparative Examples, 10 panelists engaged in the manufacture of tea beverages were selected and inspected based on the evaluation content of each item. After a consensus was reached, the evaluation with the most votes was adopted.

[0100] ◎: Although it has a strong astringency, it has the full-bodied flavor and sharpness expected of sencha. 〇: Has a strong astringency, but is somewhat lacking in full-bodied flavor as a sencha, or is somewhat dull. △: Has a strong astringency, but lacks the full-bodied flavor of sencha, or is not sharp (smells of impurities). Or has the full-bodied flavor of sencha and is sharp, but lacks astringency or is too strong.

[0101] [Table 2]

[0102] (Consideration) From the results of the above Examples and Comparative Examples, as well as the results of tests conducted by the inventors thus far, it has been found that by forming a tea leaf layer taking into consideration the hydraulic conductivity within a suitable range for each of the first tea leaves and the second tea leaves, it is possible to produce a transparent, golden-colored, packaged green tea beverage with a high concentration of tea polyphenols.

[0103] Regarding the first tea leaves that are put into the extractor first, when first tea leaves with a high hydraulic conductivity are used, the extraction time from the extractor is short, so the extraction time is insufficient, and the ratio of 580 nm to 780 nm transmittance of the obtained packaged green tea beverage is high, and the water color tends to appear slightly pale.On the other hand, when first tea leaves with a low hydraulic conductivity are used, the extraction time from the extractor is long, so the residence time of the tea extract in the extractor is long, and the ratio of 580 nm to 780 nm transmittance of the obtained packaged green tea beverage is low, and the beverage tends to appear reddish. Regarding the second tea leaves put into the extractor after the first tea leaves, it was found that when the second tea leaves with a high hydraulic conductivity were used, the extraction time from the extractor was short, so the extraction time was insufficient, and the resulting packaged green tea beverage tended to have a low tea polyphenol concentration and lack astringency.On the other hand, when the second tea leaves with a low hydraulic conductivity were used, the extraction time from the extractor was long, so the residence time of the tea extract in the extractor was long, and the resulting packaged green tea beverage tended to have a strong astringency but a rough taste.

[0104] In addition, it was found that when the first tea leaves and the second tea leaves are roasted over high heat, the hydraulic conductivity increases and the time required to extract the tea from the extractor can be shortened, but the resulting packaged green tea beverage has a lower ratio of 580 nm to 780 nm transmittance (580 nm / 780 nm), and tends to appear reddish. When a tea extract obtained by forming a tea leaf layer consisting of the first and second tea leaves and extracting the tea leaf layer in consideration of the hydraulic conductivity is diluted to a drinking level to produce a packaged green tea beverage, it has been found that the tea polyphenol concentration at which the tea leaf layer is astringent, or "strong," but not too astringent, is 86 to 200 mg / 100 mL. Similarly, when a tea extract obtained by forming a tea leaf layer consisting of the first and second tea leaves and extracting the tea leaf layer in consideration of the hydraulic conductivity is diluted to a drinking level to produce a packaged green tea beverage, it has been found that the transmittance of a packaged green tea beverage that can be evaluated as golden and transparent is 500 nm transmittance of 65% or less, particularly 45 to 64%, and the ratio of 580 nm to 780 nm transmittance (580 nm / 780 nm) is 0.85 or more, particularly 0.85 to 0.94.

Claims

1. A method for producing a packaged green tea beverage containing a tea extract obtained by drip-extracting tea leaves, comprising: Using first and second tea leaves having different hydraulic conductivity as raw materials, the first tea leaves having a larger hydraulic conductivity are put into a drip extractor, and then the second tea leaves having a smaller hydraulic conductivity are put into the extractor to form a tea leaf layer in the extractor, the tea leaf layer having a configuration in which a first tea leaf layer made of the first tea leaves is layered on a second tea leaf layer made of the second tea leaves, the tea leaf layer having a hydraulic conductivity of 70 to 93 as follows for the entire tea leaf layer; An aqueous solvent is supplied to the tea leaf layer from above, and the aqueous solvent is withdrawn from below the tea leaf layer to obtain a tea extract; The method for producing a bottled green tea beverage comprises filtering the obtained tea extract to obtain a filtrate, and compounding, sterilizing and filling the filtrate into containers. The hydraulic conductivity of the entire tea leaf layer was measured by placing each of the tea leaves in a drip extractor (with a pipe diameter of φ4 mm) as described above, and measuring the mass per unit area to be 6 g / cm ２ In a test in which a tea leaf layer is formed so that the tea leaves meet the above requirement, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from below the tea leaf layer under its own weight, the hydraulic conductivity k is calculated by the following formula. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml g / cm ２ ・s) V: Amount of tea extract extracted (mL) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

2. 2. A method for producing a bottled green tea beverage as described in claim 1, characterized in that the first tea leaves have a hydraulic conductivity of 60 or more and 90 or less, and the second tea leaves have a hydraulic conductivity of 30 or more and less than 60. The hydraulic conductivity of each tea leaf was measured by placing each tea leaf in a drip extractor (with a pipe diameter of φ4 mm) and measuring the mass per unit area of ​​6 g / cm ２ In a test in which a tea leaf layer is formed so that the tea leaves meet the above requirement, water is supplied to the tea leaf layer from above, and the tea extract is drawn out from below the tea leaf layer under its own weight, the hydraulic conductivity k is calculated by the following formula. k = (V × m) / (t × S) k: Permeability coefficient in the vertical direction (ml g / cm ２ ・s) V: Amount of tea extract extracted (mL) m: Tea leaf amount (g) S: Water flow area (cm 2 ) t: Water flow time (s)

3. 3. The method for producing a bottled green tea beverage according to claim 1 or 2, wherein the tea extract before filtration has a transmitted light absorbance value (A) of 0.12 to 0.22 at a wavelength of 660 nm.

4. 3. The method for producing a bottled green tea beverage according to claim 1 or 2, wherein the green tea beverage after being filled into the container has a tea polyphenol content of 86 to 200 mg / 100 mL%, a transmittance at 500 nm of 65% or less, and a ratio of the transmittance at 580 nm to the transmittance at 780 nm (580 nm / 780 nm) of 0.85 or more.

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